Effects of Combining Transcranial Direct Current Stimulation with Virtual Reality on Upper Limb Function in Patients with Stroke: A Systematic Review and Meta-Analysis.

Background: Persistent upper limb hemiparesis in patients with stroke can result in significant long-term disability and reduced quality of life. Transcranial direct current (tDCS) stimulation and virtual reality (VR) as stand alone or in combination are currently used for the rehabilitation of upper limb function following stroke. Objectives: The aim of this study is to determine the effects of combining tDCS with VR on level of motor impairment, motor function, spasticity, ADL, quality of life, manual dexterity, sensation, muscle strength, handgrip strength, cognitive flexibility and speed of processing, motor performance, cognition, and executive function after stroke. Design: The study is a systematic review and meta-analysis. Data Sources and Methods: PubMED, Embase, Web of Science (WoS), PEDro, and Scopus were searched until June 2023 for randomized controlled trials (RCTs) on the subject matter using the following keywords: stroke, upper extremity, upper limb, virtual reality, virtual rehabilitation, noninvasive brain stimulation, transcranial direct current stimulation, transcortical direct current stimulation, and tDCS. Methodological quality and risks of bias of the included studies were assessed using the PEDro scale and Cochrane risks of bias assessment tool, respectively. Random effect model analysis was used to compute the effect size and standardized mean difference (SMD). Results: The results showed that the included studies reported that combining tDCS with VR may improve level of motor impairment, motor function, spasticity, ADL, quality of life, manual dexterity, sensation, muscle strength, handgrip strength, cognitive flexibility and speed of processing, motor performance, cognition, and executive function. However, the result of the meta-analysis showed that it is only superior to the control at improving motor function (SMD = 0.44, 95% CI = 0.09 to 0.79, p = 0.01). Conclusions: Use of a combination of tDCS with VR may help optimize upper limb function outcomes. However, standardization of the protocol of such an intervention is needed in order to make it applicable in the real world. Registration: The study was registered in PROSPERO (registration number, CRD42023435702).